MIDTERM LEC: CLEARING Flashcards

1
Q

Removing dehydrant from tissue, and replacing it with a fluid miscible to both dehydrant and embedding agent

A

CLEARING

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2
Q

Makes tissues “transluscent” or transparent, hence the term clearing

A

CLEARING

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3
Q

Most are flammable fluids and have low boiling points

A

CLEARING

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4
Q

Excessive clearing may cause brittleness

A

CLEARING

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5
Q

Characteristics of a Clearing Agent:

A

 Miscible with alcohol, paraffin, and mounting media
 Causes minimum shrinkage
 Should not dissolve Aniline dyes
 Should not evaporate quickly in water bath
 Makes tissues transparent

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6
Q

CLEARING SOLUTIONS:

A
  1. Xylene/Xylol
  2. Benzene
  3. Toluene
  4. Chloroform
  5. Cedarwood Oil
  6. Aniline Oil
  7. Clove Oil
  8. Carbon tetrachloride
  9. Tetrachloride
  10. Methyl benzoate and Methyl salicylate
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7
Q

15-30 mins to 1hr working time (most rapid)

A

Xylene/Xylol

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7
Q

Most commonly used clearing agent

A

Xylene/Xylol

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8
Q

Colorless

A

Xylene/Xylol

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8
Q

Becomes milky when tissues are not completely dehydrated

A

Xylene/Xylol

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9
Q

Not for nervous tissues and lymph nodes because will cause hardening and shrinkage

A

Xylene/Xylol

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10
Q

Urgent biopsies and routine purposes (15 to 60 mins); very volatile in paraffin oven

A

Benzene

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11
Q

Damages the bone marrow leading to aplastic anemia

A

Benzene

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11
Q

Substitute for xylene or benzene, but slower (1-2hrs)

A

Toluene

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12
Q

Toxic upon prolonged exposure when used in high conc

A

Toluene

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13
Q

Does not cause brittleness even when tissues are left for 1 day; not carcinogenic

14
Q

For tissue blocks up to 1cm thick; recommended for large & tough tissues; CNS tissues, lymph nodes, and embryos

A

Chloroform

15
Q

Does not make tissues translucent

A

Chloroform

16
Q

Toxic to liver, tissues tend to float

A

Chloroform

17
Q

For CNS tissues and cytology, smooth muscle, skin

A

Cedarwood oil

18
Q

Becomes milky in prolonged storage

A

Cedarwood oil

19
Q

Forms crystals with acetic-alcohol fixed tses
(remedy: heat to 200OC prior to using)

A

Cedarwood oil

20
Q

For skin and smooth muscle, but tends to be adulterated

20
Q

P: for insects, embryos, and delicate tses

A

Aniline Oil

21
Properties and disadvantages are similar to chloroform but is relatively cheaper
Carbon tetrachloride
22
o For double embedding o Slow acting
Methyl benzoate and Methyl salicylate
22
Shortened turnaround time
Tetrahydrofuran
23
OTHER CLEARING SOLUTION:
1. Gum Syrup & Glycerin 2. Oil of Bergamot 3. Oil of Origanum 4. Oil of wintergreen 5. Carbon Disulfide 6. Carbol Xylene 7. Terpineol 8. Phenol 9. High Test Aviation Lead-free gasoline
24
for skin and smooth muscle
Oil of Bergamot
24
used when clearing directly from water (as in a frozen section)
Gum Syrup & Glycerin
25
for skin
Oil of Origanum
26
artificial oil, for delicate tissues
Oil of wintergreen
27
for smooth muscle; has foul odor
Carbon Disulfide
28
for friable tissues
Carbol Xylene
29
for delicate tissues like eyes
Terpineol
30
for smooth muscles
Phenol
31
excellent clearing agent
High Test Aviation Lead-free gasoline